已定义如下类模板：templateclassABC{......};则下列哪条语句是错误的？（） A: ABCobj; B: typedefABCDoubleABC; C: classDerived:publicABC{......} D: templateclassDerived:publicABC{......}

已知接口IHello和类Base､MyClass的定义如下interfaceIHello{voidHello();}classBase:IHello{publicvoidHello(){System.Console.WriteLine("HelloinBase!");}}classDerived:Base{publicvoidHello(){System.Console.WriteLine("HelloinDerived!");}}则下列语句在控制台中的输出结果为_____｡IHellox=newDerived();x.Hello(); A: HelloinBase! B: HelloinDerived! C: HelloinBase!HelloinDerived! D: HelloinDerived!HelloinBase!.